1/*
  2 * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class
  3 *
  4 * Copyright (C) 2008 Google, Inc.
  5 * Author: Mike Lockwood <lockwood@android.com>
  6 *
  7 * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
  8 * (originally switch class is supported)
  9 *
 10 * This software is licensed under the terms of the GNU General Public
 11 * License version 2, as published by the Free Software Foundation, and
 12 * may be copied, distributed, and modified under those terms.
 13 *
 14 * This program is distributed in the hope that it will be useful,
 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 17 * GNU General Public License for more details.
 18 */
 19
 20#include <linux/extcon.h>
 21#include <linux/extcon/extcon-gpio.h>
 22#include <linux/gpio.h>
 23#include <linux/gpio/consumer.h>
 24#include <linux/init.h>
 25#include <linux/interrupt.h>
 26#include <linux/kernel.h>
 27#include <linux/module.h>
 28#include <linux/platform_device.h>
 29#include <linux/slab.h>
 30#include <linux/workqueue.h>
 31
 32struct gpio_extcon_data {
 33	struct extcon_dev *edev;
 34	int irq;
 35	struct delayed_work work;
 36	unsigned long debounce_jiffies;
 37
 38	struct gpio_desc *id_gpiod;
 39	struct gpio_extcon_pdata *pdata;
 40};
 41
 42static void gpio_extcon_work(struct work_struct *work)
 43{
 44	int state;
 45	struct gpio_extcon_data	*data =
 46		container_of(to_delayed_work(work), struct gpio_extcon_data,
 47			     work);
 48
 49	state = gpiod_get_value_cansleep(data->id_gpiod);
 50	if (data->pdata->gpio_active_low)
 51		state = !state;
 52
 53	extcon_set_state_sync(data->edev, data->pdata->extcon_id, state);
 54}
 55
 56static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
 57{
 58	struct gpio_extcon_data *data = dev_id;
 59
 60	queue_delayed_work(system_power_efficient_wq, &data->work,
 61			      data->debounce_jiffies);
 62	return IRQ_HANDLED;
 63}
 64
 65static int gpio_extcon_init(struct device *dev, struct gpio_extcon_data *data)
 66{
 67	struct gpio_extcon_pdata *pdata = data->pdata;
 68	int ret;
 69
 70	ret = devm_gpio_request_one(dev, pdata->gpio, GPIOF_DIR_IN,
 71				dev_name(dev));
 72	if (ret < 0)
 73		return ret;
 74
 75	data->id_gpiod = gpio_to_desc(pdata->gpio);
 76	if (!data->id_gpiod)
 77		return -EINVAL;
 78
 79	if (pdata->debounce) {
 80		ret = gpiod_set_debounce(data->id_gpiod,
 81					pdata->debounce * 1000);
 82		if (ret < 0)
 83			data->debounce_jiffies =
 84				msecs_to_jiffies(pdata->debounce);
 85	}
 86
 87	data->irq = gpiod_to_irq(data->id_gpiod);
 88	if (data->irq < 0)
 89		return data->irq;
 90
 91	return 0;
 92}
 93
 94static int gpio_extcon_probe(struct platform_device *pdev)
 95{
 96	struct gpio_extcon_pdata *pdata = dev_get_platdata(&pdev->dev);
 97	struct gpio_extcon_data *data;
 98	int ret;
 99
100	if (!pdata)
101		return -EBUSY;
102	if (!pdata->irq_flags || pdata->extcon_id > EXTCON_NONE)
103		return -EINVAL;
104
105	data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
106				   GFP_KERNEL);
107	if (!data)
108		return -ENOMEM;
109	data->pdata = pdata;
110
111	/* Initialize the gpio */
112	ret = gpio_extcon_init(&pdev->dev, data);
113	if (ret < 0)
114		return ret;
115
116	/* Allocate the memory of extcon devie and register extcon device */
117	data->edev = devm_extcon_dev_allocate(&pdev->dev, &pdata->extcon_id);
118	if (IS_ERR(data->edev)) {
119		dev_err(&pdev->dev, "failed to allocate extcon device\n");
120		return -ENOMEM;
121	}
122
123	ret = devm_extcon_dev_register(&pdev->dev, data->edev);
124	if (ret < 0)
125		return ret;
126
127	INIT_DELAYED_WORK(&data->work, gpio_extcon_work);
128
129	/*
130	 * Request the interrupt of gpio to detect whether external connector
131	 * is attached or detached.
132	 */
133	ret = devm_request_any_context_irq(&pdev->dev, data->irq,
134					gpio_irq_handler, pdata->irq_flags,
135					pdev->name, data);
136	if (ret < 0)
137		return ret;
138
139	platform_set_drvdata(pdev, data);
140	/* Perform initial detection */
141	gpio_extcon_work(&data->work.work);
142
143	return 0;
144}
145
146static int gpio_extcon_remove(struct platform_device *pdev)
147{
148	struct gpio_extcon_data *data = platform_get_drvdata(pdev);
149
150	cancel_delayed_work_sync(&data->work);
151
152	return 0;
153}
154
155#ifdef CONFIG_PM_SLEEP
156static int gpio_extcon_resume(struct device *dev)
157{
158	struct gpio_extcon_data *data;
159
160	data = dev_get_drvdata(dev);
161	if (data->pdata->check_on_resume)
162		queue_delayed_work(system_power_efficient_wq,
163			&data->work, data->debounce_jiffies);
164
165	return 0;
166}
167#endif
168
169static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume);
170
171static struct platform_driver gpio_extcon_driver = {
172	.probe		= gpio_extcon_probe,
173	.remove		= gpio_extcon_remove,
174	.driver		= {
175		.name	= "extcon-gpio",
176		.pm	= &gpio_extcon_pm_ops,
177	},
178};
179
180module_platform_driver(gpio_extcon_driver);
181
182MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
183MODULE_DESCRIPTION("GPIO extcon driver");
184MODULE_LICENSE("GPL");